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Wednesday, November 25, 2009

A BiPAP Q&A session

I've been getting a lot of questions about BiPAP*recently, so I thought I'd take some time to answer your questions about this wonderful machine. You can learn the basics of BiPAP by cliciking on the link above.

1. What are the best initial settings to use on a critical patient?: I think most RTs will agree that the best setting to start a patient on BiPAP is an IPAP of 10 and an EPAP of 4, and to titrate to the patient tolerance from there. I think that's a good rule of thumb. FiO2 should be set as low as possible to maintain an acceptable saturation, usually around 90%.

2. What is the risk of refusing a BiPAP machine?: Actually -- ironically -- I just got called to set up a BiPAP on a patient who has refused it the past three nights. He's still alive, but barely. There are a lot of patients who refuse to have that mask over their faces, and I can understand that. But when it is used and tolerated, it can do a lot of good. In the case of this patient, it is needed to keep his lungs open and to provide some CPAP to keep his oxygen level up. His SpO2 at present is 55%. His CO2 is high also, and the IPAP would help to give him better tidal volumes to blow off some of that CO2. So, the risk for this individual is actually death. Sure the BiPAP may be inconvenient and uncomfortable, but it can be a life saving machine.

This particular patient was a DNR. If he wasn't, the risk of refusing the BiPAP would mean that to oxygenate and ventilate this man we would have to insert an ETT in his throat and to his lungs and hook him up to a ventilator.

Most patient who require a BiPAP do so for other reasons. For instance, sometimes a BiPAP machine is recommended to prevent desaturations while sleeping and to treat sleep apnea. If the BiPAP will allow you to stay oxygenated while sleeping, and keep you ventilating while you sleep, the alternative could mean that you will be risking death.

3. Is it hard to get used to BiPAP?: I asked this to all my patients who tolerate it or grow to love it and just
about all of them say it is hard at first, but the machine helps them to feel so much better than they quickly learned to tolerate it. I find that the new BiPAP machines (like the Vision in the picture) work so well with the patient, and the new masks are so comfortable, that most patients tolerate it quite well. I guess my point here is that I recommend to RT departments to splurge and get the best BiPAP machines and the best masks available, it's worth it.

4. What kind of BiPAP machine is best?: I highly recommend a high quality BiPAP machine like the Vision as opposed to a machine that is made to be used as a Ventilator but also has the BiPAP option like the LTV 1200. Sure the LTV has BiPAP, but it's not near as good as machines made to be used only for BiPAP. The Vision is also very easy to set up. I'm not trying to sell the Vision here, it's just the BiPAP machine we have, and I love it. If you have a BiPAP machine you love, list it in the comments below.

5. Are BiPAP machines in hospital different from those used by patients at home?: Yes. When a patient is admitted to the hospital for a reason other than for a respiratory related issue I recommend that they bring their BiPAP machine from home. Their home machine is tailored to fit their face, and they are also used to it. We have gone out of our way to get the best machines and masks, but they are never as good as what patients have at home. Now, if a patient is admitted with respiratory distress, I like to use our machines so we can control the settings a little better, watch graphics, and set alarms. Basically, the in-hospital BiPAP machines have more bells and whistles.

6. Do BiPAP machines prevent people from needing a ventilator?: Yes. I find that there are many patients who, if they tolerate the BiPAP, can prevent themselves from needing to be placed on a ventilator. In fact, since we purchases our Visions five years ago the number of ventilator cases has diminished by almost 80%.

7. At what point do you take a patient off the BiPAP to intubate?: That's a good question. You will want to ventilate any full code patient who absolutely cannot tolerate or refuses the BiPAP and continues to fail. A BiPAP can even be used on a DNR patient. If they continue to fail despite the BiPAP, then you will have no choice but to intubate. However, it is possible to set a rate on the Vision. But as a rule of thumb, if the patient has no rate, ventilate.

8. What patients other than sleep apnea is BiPAP good for?: BiPAP works well for CHF, COPD and even asthma. I have seen it work wonders for all three diseases. While some studies show that CPAP should be used for CHF and BiPAP for COPD, I recommend skipping the CPAP an jumping right to BiPAP. That way you can control the patients oxygen with the EPAP and his ventilations with the IPAP. Great machine.

9. When should BiPAP be discharged?: That depends on what you are using it for. If you are using it because the patient came into the ER in respiratory distress, then you can take it off as soon as the patient is able to ventilate on his own, and oxygenate with just supplemental oxygen. Basically, you only want to place a patient on a machine like this only to rest their lungs to help them get over the hump. Once the patient is able to ventilate and oxygenate without the machine they should be taken off of it. However, if the machine is being used to oxygenate and/or ventilate a patient while he is sleeping, it may be required permanently. However, a patient should regularly see his or her physician, and if the patient progresses enough to no longer require the machine it can be discharged. An example of a patient no longer requiring it would be a 400 pound man who lost 200 pounds and no longer had sleep apnea. However there may be other reasons for discontinuing this machine.

Any further questions or comments please emal me or leave a comment below. To read about indications for BiPAP, click here.

*Note: BiPAP is a patented name or a brand name. Ideally this device should be referred to as non-invasive positive pressure ventilation (NPPV).

24 comments:

medic.dan
said...

Thanks for this informative post! I work on an ambulance and we are just starting to see CPAP use for CHF/COPD in the field, often in leiu of intubation (ultimately great for the patient). In the hospital, when will you use BiPAP over CPAP for CHF/COPD? Can you explain the differences please?Thanks!

Have you worked with the new V60 bipap machine? It's pretty damn cool and works well for peds.

You can use vision bipap on peds, but have to dial in the normal patient resp. rate for that age, because they can't trigger. In the V60 there is enough bias flow in the circuit to support their breathing and trigger effort. It's great for status asthmaticus.

I think it depends on the situation and the patient. If the patient is in respiratory distress, it is sometimes necessary to treat before test results are performed (i.e., before ABGs, x-rays, labs, etc.) For example, a patient in obvious heart failure may benefit from the decreased preload BiPAP can provide. For a COPD patient, the BiPAP can help witho oxygenation (FiO2 & EPAP) and ventilation (IPAP). Also, with noninvasive testing such as SpO2 and ETCOT, he could base his decision on those, as opposed to the ABG. Personally, I think ABGs are over ordered, and a VBG would be all that is necessary to get a pH.

how do you use the rate? does it actually trigger a set rate? no one I work with uses it. they say it doesn't do anything, but Heidi uses it to trigger for infants. I'm confused what the rate actually does

When I have a patient who needs to blow off CO2 I set the rate high(20+),but the people where I work think I'm wrong. They say the patient sets the rate. I work in a teaching hospital so I don't want to be wrong for the residents. I would hate to be teaching them wrong info. We are switching to the V60 soon. I hope we get some education then, but it's a VA hospital, so I doubt it. Thank you for this web site. I really appreciate it and I'm very glad to have stumbled into it.Thanks again.

I believe you are correct. If you set the back up rate at 6, and the patient rate is 0, will not the unit guarantee that rate of 6? I know it does, because I have seen it happen many times. So if this is true, then why can't you set the back up rate at 10, or even 20? You can, and I have done it on occasion. However, I have not seen any medical literature to prove this.

There is yet another myth I often find worshiped by other RTs and physicians, and that is that you have to have settings higher than 10/4 to be therapeutic. I find this to be poppycock, because it is not the number that you are concerned with, but the minute ventilation. You want the minimum settings necessary to maintain an adequate minute ventilation, even if those settings are 10/4 or even less. Do not give in to the myths, because they are abounding.

Hi Rick, Thanks for your great work! I have a family member with advanced COPD.Please give us your wisdom and input regarding this opinion from one medical professional: 1)BiPAP machines are only used in emergency rooms, and require such a highly trained technicians that they are not to be used in hospitals and nursing homes. 2)Home use machines are too complicated to be operated by someone other than a trained technician. 3)BiPAP machines that can be rented or purchased for home use are virtually useless for expelling CO2 because they don't create enough pressure on the lungs.

Home BiPAP machines are equally as effective as the ones used in the hospital setting. The only difference is the ones we use have additional to warn us if a patient stops breathing, breaths too fast, etc.

I have a question, my dad is end stage COPD/ emphysema. He is using bipap at home but his "pressure" has needed to be steadily decreased for him to tolerate it. Does that means his lungs are getting worse?

BurnsFamily: It could also mean that he is getting better. As lungs become more compliant they may need less pressure to generate the same tidal volume. I would recommend talking to your dad's physician.

I have serious Asthma cough that is productive. I am also on a Bi-pap machine. I notice at night when I get my machine all set and my mask on within a few minutes I am coughing so bad I have to rip the mask off...